DE102012112631A1 - CONTROL PROCEDURE FOR A VEHICLE WITH DOUBLE CLUTCH GEAR - Google Patents

Abstract

A clutch slip can be minimized with a method for different control of the clutch depending on the current driving state of the vehicle, if the vehicle is accelerated again with two open clutches before the vehicle is stopped with a dual clutch transmission (DCT). The method can improve a shift feeling by optimizing the slope of an engine speed.

Description

The present application claims the priority of Korean Patent Application No. 10-2012-0119270 , filed Oct. 25, 2012, the entire contents of which are incorporated herein for all purposes by this reference.

The present invention relates to a control method for a vehicle having a dual-clutch transmission (DCT), and more particularly to a control method of a vehicle when there is a request for re-acceleration (or re-acceleration) in an opened clutch before the vehicle stops.

In vehicles with a dual-clutch transmission (DCT), which does not use a torque converter but a clutch as a starting device, the clutch is opened (or disengaged) before stopping to prevent a shock due to engine shutdown (engine) ) and to prevent a change of direction of the engine torque.

With this configuration, when a driver depresses the accelerator pedal to re-accelerate the vehicle, it is necessary to re-accelerate the vehicle by shifting the clutch of an input shaft (hereinafter: target shaft) to which a target gear (or target gear stage), which is determined on the basis of the current driving state of the vehicle belongs, is controlled. Such a startup control, as in 1 is a type of control of a clutch in consideration of engine torque so that an engine speed satisfies an engine target speed by appropriately setting the engine target speed according to the running state of the vehicle.

However, when the start control is performed under the condition that the clutch speed of the target shaft is higher than the current engine speed, the inertia of the input shaft is smaller than the inertia of the engine (internal combustion engine), the engine speed and the rotational speed of the target shaft being mutually different so that a shock can be generated upon engagement of the clutch, and the higher the target gear, the more the durability of the clutch may decrease due to the excessive slip.

For example, in 1 Although the target shaft is an input shaft to which the first clutch is connected, and the clutch is structurally disposed between an engine and the input shaft, for convenience, it will be understood that the rotational speed of the first clutch is the rotational speed of the input shaft is the target shaft, derived from the fact that the clutch rotates integrally with the input shaft.

The information disclosed herein in connection with the background of the invention is merely for the better understanding of the general background of the invention and should not be taken as an acknowledgment or any form of indication that this information represents a prior art already known to those skilled in the art.

Various aspects of the present invention have been made in an effort to solve the above-mentioned problems associated with the prior art.

Various aspects of the present invention provide a control method for a vehicle having a dual clutch transmission (DCT) that can minimize slip of a clutch by differently executing the method of controlling the clutch depending on the current driving state of the vehicle when the vehicle is re-accelerated at two open clutches before stopping the vehicle with the DCT, and which can improve the shift feel by optimizing the slope (or gradient) of engine speed.

Various aspects of the present invention provide a control method for a vehicle having a DCT, the method comprising: a reacceleration determining step of determining whether a request from a driver for re-acceleration exists with two clutches open; and a rotational speed taking-in step for changing a clutching process of a clutch of a target shaft which includes an input shaft to which a target gear determined according to a current vehicle speed of the vehicle is, depending on the magnitude of a current engine speed and speeds of input shafts to which the two clutches are connected.

The methods and apparatus of the present invention have further features and advantages as will become apparent in more detail from the attached drawings, which are incorporated herein by reference, and the following detailed descriptions, which together serve to explain certain principles of the present invention.

1 FIG. 15 is a diagram showing a control method for a vehicle having a dual-clutch transmission (DCT) according to FIG Technique shows and illustrates an example of a start control.

2 FIG. 10 is a flowchart illustrating an exemplary control method for a vehicle having a DCT according to the present invention. FIG.

3 FIG. 12 is a diagram illustrating an exemplary engagement control process in a control method for a vehicle having a DCT according to the present invention. FIG.

4 FIG. 15 is a diagram illustrating an exemplary non-engagement control process in a control method for a vehicle having a DCT according to the present invention. FIG.

It should be understood that the appended drawings are not necessarily to scale, presenting merely a simplified representation of the various features in accordance with the principles of the invention. The particular design features of the present invention as disclosed herein, including, for example, particular dimensions, orientations, locations and outlines, will be determined in part by a particular intended application and usage environment.

In the figures, like reference characters designate the same or corresponding parts of the present invention in all different figures of the drawings.

Reference will now be made in detail to the various embodiments of the present invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the embodiments, it will be understood that the present description is not intended to limit the inventions to those exemplary embodiments. On the other hand, it is intended that the invention not only cover the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that fall within the spirit and scope of the invention as defined in the appended claims.

It should be understood that the term "vehicle" or other similar terms used herein includes motor vehicles, such as motorized vehicles, in general. Passenger cars including SUVs, buses, trucks, various commercial vehicles, watercraft including a variety of boats and vessels, aircraft and the like, as well as hybrid vehicles, electric vehicles, plug-in hybrids. Electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (eg fuels derived from non-petroleum resources). As referred to herein, a hybrid vehicle is a vehicle having two or more drive means, such as a vehicle. B. vehicles with both gasoline and electric drive.

Referring to 2 10, a control method for a vehicle having a dual clutch transmission (DCT) according to various embodiments of the present invention: a re-acceleration determination step S10 for determining whether there is a request from a driver for re-acceleration, two clutches being open (disengaged); and a speed consideration step 830 for changing a clutch of a target shaft, which is an input shaft that has detected a target gear according to a current vehicle speed, depending on the height of the current engine speed and the speed of input shafts to which the two clutches are connected are.

That is, according to the present invention, it is possible to improve the shift feeling by optimizing the gradient of an engine speed to reduce a shock when engaging the clutch and to improve the durability of the clutch by minimizing a clutch slip when a driver intends re-accelerating a vehicle by stepping down an accelerator pedal at two open clutches before deceleration and stop by detecting the intention in the re-acceleration detection step S10 and comparing the rotational speeds of the engine and the two input shafts at that time and by implementing the processes from engaging the clutch of the target shaft to re-accelerating the vehicle in different ways.

The speed considering step S30 compares the current engine speed with the speed of the target shaft and defines: the first case where the current engine speed is equal to or higher than the speed of the target shaft; the second case, wherein the current engine speed is less than the rotational speed of the target shaft (or target shaft speed) and greater than the rotational speed of an engagement shaft (or interlock shaft), which is the other input shaft adjacent to the target shaft; and the third case, wherein the engine speed is less than the rotational speed of the target shaft and the rotational speed of the engagement shaft.

That is, the first case where the engine speed is higher than the target shaft speed, the second case wherein the target shaft speed is greater than the engagement shaft speed and the engine speed is between the target shaft speed and the engagement shaft speed and the third case wherein the engine speed is less than both the target shaft speed and the engagement shaft speed.

In the first case, a start control process S31 that sets an engine target rotation speed according to the running state of a vehicle and controls and engages the target shaft coupling in consideration of engine torque such that the engine rotation speed satisfies the engine target rotation speed is performed.

That is, when the engine speed is equal to or higher than the rotational speed of the target shaft, the clutch of the target shaft is engaged by performing start control in the same manner as the related art.

In the second case, an engagement control process S32 (interlock control process of both the target and engagement shafts for bringing them into engagement with the engine) which operates the clutch of the target shaft and the clutch of the engagement shaft is performed so that they are brought into engagement until the engine speed reaches the speed of the target shaft, and then the engagement of the clutch of the target shaft is completed by means of a hand-over.

That means: as in 3 shown, when the engine speed is an intermediate value which is lower than the rotational speed of the target shaft and higher than the rotational speed of the engagement shaft, a process of formation of an engaged state (interlock state), in which both clutches are substantially engaged with the engine, is performed by the clutch of the engagement shaft is actuated to also be simultaneously engaged with the engagement of the clutch of the target shaft, which prevents the rapid increase of the engine speed due to the engagement of the engagement shaft coupling and controls the slope gently, thus preventing a shock.

The engagement of the target shaft clutch is completed by a transfer disengaging the engagement shaft clutch and engaging the target shaft clutch after the engine speed has reached the target shaft speed, wherein an engagement state is formed by engaging both clutches. Therefore, it is possible to effectively reduce a shift shock generated upon operation in the related art, and more effectively reduce the shift shock by performing engine cooperative control that reduces engine torque from a time point when engine speed becomes high the target shaft speed, until a time when the engagement of the clutch is completed requests.

For example, the clutch of a target shaft is shown as a first clutch and the clutch of an engagement shaft as a second clutch.

In the third case, as in 4 2, a non-engagement control process S33 (or non-interlock control process) is performed, which engages the clutch of the target shaft, and the engine speed is controlled according to the rotational speed of the target shaft. For example, the coupling of a target shaft as a second clutch in 4 shown.

That is, when the engine rotational speed is less than both the rotational speed of the target shaft and the rotational speed of the engagement shaft, a shift shock, unlike the start control, can be effectively reduced by controlling the engine rotational speed according to the target shaft rotational speed and performing the engine cooperative control, which requests a reduction in engine torque from a point in time when the engine speed approaches the target shaft speed until a time when the clutch is engaged.

As described above, in the engagement control process S32 and in the disengagement control process S33, engine cooperation control for requesting the reduction of the engine torque is performed from a timing when the engine rotational speed reaches 90% or more of the rotational speed of the target shaft until a timing when the engagement of the clutch is completed.

Before the speed consideration step S30, there is further included a target gear determination step S20 which determines whether a target gear is the third gear or a higher gear, and it is determined whether the first case is when as the result of the target gear determination step S20 the target gear is not the third gear or higher, and it is determined whether the second or the third case is when the gear is the third gear or a higher gear.

That is, when the start control process S31 is performed with the target gear at the third or higher gear, a slip time becomes too long, and to avoid this, it is not determined whether the first case exists but basically whether the second one or the third case is when the gear is the third or higher gear, so that a clutch is engaged by the engagement control process S32 or the disengagement control process S33.

If, as the result of the target gear determination step S20, the gear is not the third gear or is higher and it is determined whether the first case exists, and when the result is determined that the first case is present, of course, the start control process S31 is performed, and if the first case is not present, it is also determined whether the second or the third case is present so that the engagement control process S32 or the disengagement control process S33 can be performed.

As described above, according to the present invention, when there is a request from a driver for re-acceleration with two clutches open, it is possible to minimize slippage of the clutches and improve the shift feeling by optimizing the slope of the engine speed and the process of stopping the engagement of an input shaft to which a target gear belongs is changed depending on the height of the target gear determined according to the current vehicle speed and the height relationship between the current engine speed and the angular speeds of the two input shafts.

The present invention can minimize slippage of a clutch by making the method of controlling the clutch different depending on the current driving state of the vehicle when the vehicle is accelerated again in two open clutches before stopping the vehicle with the DCT, and can Improve the shift feel by optimizing the slope of an engine speed.

The foregoing descriptions of the specific exemplary embodiments of the present invention are for the purpose of illustration and description. They are not to be construed as exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teachings. The exemplary embodiments have been chosen and described to illustrate certain principles of the invention and its practical application, and to enable those skilled in the art to make and use the various embodiments of the present invention, as well as the numerous alternatives and modifications thereof. It is intended that the scope of the invention be defined by the appended claims and their equivalents.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• KR 10-2012-0119270 [0001]

Claims (6)

A control method for a vehicle having a dual clutch transmission (DCT), comprising: a reacceleration determining step (S10) of determining whether there is a request from a driver for re-acceleration, two clutches being open; and a speed consideration step (S30) for changing a clutch engagement process of a target shaft that includes an input shaft to which a target gear determined according to a current vehicle speed of the vehicle is dependent on the magnitude of a current engine speed and rotational speeds of Input shafts to which the two clutches are connected. The method of claim 1, wherein the speed-taking step (S30) compares a current engine speed with a speed of the target shaft and defines: a first case where the current engine speed is equal to or higher than the speed of the target shaft; a second case wherein the instantaneous engine speed is less than the rotational speed of the target shaft and greater than a rotational speed of an engagement shaft which is the other input shaft other than the target shaft; and a third case wherein the engine speed is less than the rotational speed of the target shaft and the rotational speed of the engagement shaft. The method of claim 2, wherein: in the first case, a start control process (S31) sets an engine target rotational speed in accordance with the running state of a vehicle, and controls and engages the clutch of the target shaft based on an engine torque so that the engine rotational speed satisfies the engine target rotational speed; in the second case, an engagement control process (S32) operates the clutch of the target shaft and the clutch of the engagement shaft so that they are brought into engagement until the engine speed reaches the rotational speed of the target shaft, and then completes the engagement of the clutch of the target shaft by means of a transfer ; and in the third case, a non-engagement control process (S33) engages the clutch of the target shaft, wherein the engine speed is controlled according to the rotational speed of the target shaft. The method of claim 3, wherein in the engagement control process (S32) and in the disengagement control process (S33), engine cooperation control for requesting reduction of engine torque is performed from a time point when the engine speed is 90% or more of the revolution speed of the engine Target shaft reached until a time when the clutch engagement is completed. The method of claim 3, further comprising a target gear determination step (S20) before the speed considering step (S30), which determines whether a target gear is the third gear or higher, and determines whether the first case exists, when, as the result of the execution of the target gear determination step (S20), the target gear is not the third gear or higher, and it is determined whether the second or the third case exists when the gear is the third gear or higher. The method according to claim 5, wherein if, as the result of the target gear determination step (S20), the gear is not the third gear or higher, and further determines that the first case is not established, it is determined whether the second or the third one Case exists.

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